The current structural composite connecting rods for reacting axial forces typically have an elongated shape with a central primary body ending with two flat ends for connecting to structures in particular creating axial traction-compression forces, the connection typically being done by connecting axes respectively mounted through these ends.
Document WO-A1-2009/000925 describes such a connecting rod, which is obtained via a method comprising discontinuous thermoforming of flat composite preforms based on fibers impregnated with a thermosetting or thermoplastic resin to obtain two semi-cylindrical shells, then an assembly of these thermoformed shells by lateral securing of the respective pairs of longitudinal edges preferably via curing or thermowelding of the resin. This assembly of the shells is such that each edge of a shell covers or is laterally covered by an edge of the other shell, thus forming mutual support surfaces for these shells with relatively large surface areas.
The connecting rods described in this document have the drawback of having a relatively high mass and manufacturing cost, due to their discontinuous manufacturing method and the assembly mode of the shells by lateral overlapping of their edges, which requires doubling the thickness of the connecting rod.
More generally, one major drawback of the structural composite connecting rods known at this time lies in their high mass and cost, which are related on the one hand to the conversion method used, typically resin transfer molding (RTM) or molding of preimpregnated fibers of a resin that is also thermosetting, by compression in a mold using a bladder or mandrels, and on the other hand, reinforcing these connecting rods to give them sufficient impact strength. The quantity of reinforcements necessary to guarantee impact strength can be relatively high. Indeed, thermosetting resins for example of the epoxy type are extremely fragile due to their very weak elongation at break (typically several %). It is therefore necessary to add a number of plies inversely proportional to this elongation at break to make these resins better able to withstand deformation during impact, which contributes to making these connecting rods made from thermosetting materials heavier.